Steve Jobs returned from his medical leave to present in San Francisco more novelties, including the iCloud service through which users’ files can be stored on Apple’s servers, they being able to easily access them from anywhere, using iPhone, iPad, iPod touch or other Apple products.

Companies like Google, Amazon and Microsoft have massively promoted the cloud computing, and Apple hopes to catch them up, helped by their efficient marketing.

“The iCloud stores your content in the cloud and wirelessly pushes it to all your devices," said Steve Jobs, who held a presentation in his style. He admitted that it’s annoying to have to synchronize with your PC order to transfer various files on them and added that iCloud is the solution because if the user buys a song from iTunes for example, it will be loaded automatically "in the cloud" and a user can easily access it via internet using any Apple device, without needing to synchronize these devices separately.

Jobs says that iCloud was necessary because the PC is no longer the center of the "digital life", the PC drops in rank, being a simple device. He added that iCloud “is not only a hard disk in the sky", but is wanted to be "the latest great idea of us".

iCloud is free except for an option that an iTunes version, called Match, scans and then sends into the cloud songs that users owned on their Apple devices without being bought from iTunes. Users will be able to listen to those songs anywhere, on any Apple terminal, but will have to pay an annual subscription fee of $ 25 for the privilege of listening to these songs.

The free iCloud services include:

The former MobileMe services—Contacts, Calendar and Mail—all completely re-architected and rewritten to work seamlessly with iCloud. Users can share calendars with friends and family, and the ad-free push Mail account is hosted at me.com. The inbox and mailboxes are kept up-to-date across all user’s iOS devices and computers.

The App Store and iBookstore now download purchased iOS apps and books to all your devices, not just the device they were purchased on. In addition, the App Store and iBookstore now let you see your purchase history, and simply tapping the iCloud icon will download any apps and books to any iOS device (up to 10 devices) at no additional cost.

iCloud Storage seamlessly stores all documents created using iCloud Storage APIs, and automatically pushes them to all your devices. When you change a document on any device, iCloud automatically pushes the changes to all your devices. Apple’s Pages, Numbers and Keynote apps already take advantage of iCloud Storage. Users get up to 5GB of free storage for their mail, documents and backup—the storage for music, apps and books purchased from Apple, and the storage required by Photo Stream doesn’t count towards this 5GB total. Users will be able to buy more storage, with details announced when iCloud ships this fall.

iCloud’s Photo Stream service automatically uploads the photos you take or import on any of your devices and wirelessly pushes them to all your devices and computers. Photo Stream is built into the photo apps on all iOS devices, iPhoto on Macs, and saved to the Pictures folder on a PC. To save space, the last 1,000 photos are stored on each device so they can be viewed or moved to an album to save forever. Macs and PCs will store all photos from the Photo Stream, since they have more storage. iCloud will store each photo in the cloud for 30 days, which is plenty of time to connect your devices to iCloud and automatically download the latest photos from Photo Stream via Wi-Fi.

iTunes in the Cloud lets you download your previously purchased iTunes music to all your iOS devices at no additional cost, and new music purchases can be downloaded automatically to all your devices. In addition, music not purchased from iTunes can gain the same benefits by using iTunes Match, a service that replaces your music with a 256 kbps AAC DRM-free version if Apple can match it to the over 18 million songs in the iTunes Store, it makes the matched music available in minutes, and uploads only the small percentage of unmatched music. iTunes Match will be available this fall for a $24.99 annual fee.

According to Apple, they are ready to ramp iCloud in its three data centers, including the third recently completed in Maiden, NC. Apple has invested over $500 million in its Maiden data center to support the expected customer demand for the free iCloud services.